Error detecting printer in high speed printing apparatus



Oct. 24, 1967 R. A. PANDOLFI ERROR DETECTING PRINTER IN HIGH SPEED PRINTING APPARATUS Original Filed Aug 6, 1964 \NVENTOR 001/1204 ens p01 F/ WQTQEZ EY United States Patent 3,348,479 ERROR DETECTING PRINTER IN HIGH SPEED PRINTING APPARATUS Richard A. Pandolfi, Haupauge, N.Y., assignor to Potter Instrument Company, Inc., Piainview, N.Y., a corporation of New York Continuation of application Ser. No. 387,935, Aug. 6, 1964. This application Sept. 27, 1966, Ser. No. 582,461 5 Claims. (Cl. 10193) The application is a continuation of application Ser. No. 387,935, filed Aug. 6, 1964, now abandoned.

This invention, generally, relates to high speed printing apparatus and, more particularly, to a high speed printing apparatus with means to print a special character indicting the validity or invalidity of the printed information.

In high speed printers of the type which print characters selected by applied electronic signals, there is a need for an indication, directly on the medium on which the printing is being carried out, of the validity of the printed information. This is particularly true when the printed information is numerical or in code because an error in such information will not necessarily be evident from the content of the information. The present invention is directed to satisfying this need.

The system of the present invention is used with a printer in which the characters to be printed are raised in relief on a drum, which is rotated at a high speed. A row of hammers, actuated by solenoids, are positioned to extend axially along the drum. The paper on which the printing is to be carried out is positioned, along with an ink ribbon, between the hammers and the drum. The solenoids, when energized, activate the hammers to strike the paper against the drum as the drum rotates. By timing the energization of the solenoids relative to the drum position, any desired character can be printed on the paper beneath each hammer, and in this manner, an entire line of characters can be printed. The paper is advanced incrementally to print additional lines of characters.

In accordance with the present invention, a continuous pattern raised in relief is formed on the drum extending circumferentially around the drum.- An additional hammer, actuated by a solenoid, is provided opposite this pattern, so that when the solenoid of this additional hammer is energized, a character having the form of the continuous pattern will be printed. This character is used to indicate whether the line of print opposite which it is printed contains an error and is referred to as a validating character.

Because the validating character is printed from a continuous pattern extending around the drum in a ring, the validating character can be printed atany time, even when the paper is moving, and the energization of the solenoid which actuates the hammer to print the validating character does not have to be synchronized with the drum. This feature is a great advantage because it eliminates the time which normally would be required for the error indicating signal to be synchronized with the drum and, thus, leaves more time for the error detecting means to function.

Accordingly, an object of the present invention is to provide in a high speed printing apparatus means to indicate whether or not there is an error in the printed information.

Another object of the present invention is to provide a high speed printing apparatus with means to print a character to indicate whether or not the printed information is valid.

Another object of the present invention is to provide a high speed printing apparatus of the type which prints characters from a rotating drum with means to print a special character, which can be printed at any time regardless of the position of the drum.

A still further object of the present invention is to provide more time for the error detecting means to function in a high speed printer with means to print a character to indicate whether or not the printed information is valid.

Further objects and advantages of the present invention will become readily apparent as the following detailed description of a specific, presently preferred embodiment of the invention unfolds, and when taken in conjunction With the drawings, wherein the single figure is a schematic illustration of the system of the invention.

As shown in the drawing, the high'speed printer of the present invention includes a drum 11, which is rotated at high speed by a motor 12. Axially extending rows of alphanumeric characters are defined on the drum, all of the alphanumeric characters'in any given row being the same. The rows of characters are aligned so that they define circumferential rings of alphanumeric characters with each ring of characters containing all of the alphanumeric characters used on the drum and to be printed 'by the apparatus.

A row of solenoid-actuated hammers 13 is positioned axially along the drum with each hammer opposite a different circumferential ring of alphanumeric characters. Paper on which the printing is to be carried out is fed, along with an inked ribbon, between the faces of the hammers 13 and the drum 11. p

The characters are raised in relief on the drum so that when the solenoids of the hammers 13 are energized, the hammers strike the paper against the drum to print whatever characters are beneath the hammers on the paper. The energizing of the'hammer solenoids to cause them to strike against the drum is referred to as firing the hammers. By controlling when the hammers 13 are fired relative to the position of the drum 11 as it rotates, any desired character can be printed under each hammer and any desired line of characters can be printed in one drum revolution.

The reference number 15 designates electrical circuitry for controlling the printing of the alphanumeric characters. The control circuitry 15 continuously detects the position of the drum 11 by means of a tone wheel 17 driven directly by the drum. The control circuitry 15 controls the firing of the hammers 13 relative to the drum position, in accordance with coded input signals, to print characters selected by the coded input signals. When a line of characters has been'printed, the paper is advanced one increment so that the next line of characters can be printed.

The high speed printer, as described above, is well known, and the control circuitry 15 for controlling the fir ing of the hammers 13 in accordance with applied coded input signals is described, for example, in the patent to Wasserman No. 3,024,723.

In accordance with the present invention, a continuous pattern 21 raised in relief is formed in a circumferential ring extending around the drum 11. While any desired configuration may be selected for the continuous pattern 21, in the preferred embodiment it is in the form of a herringbone. Instead of a herringbone, for example, a pair of parallel lines extending around the drum or another continuous pattern could be used.

A solenoid-actuated hammer 23 aligned with the hammers 13 is positioned opposite the pattern 21. The paper and the inked ribbon, which are fed between the drum 11 and the hammers 13, extend between the hammer 23 and the pattern 21 so that when the hammer 23 is fired to strike the paper against the pattern 21, a symbol in the form of the pattern 21 is printed on the paper opposite the character line currently under the hammers 13.

In this character line, the characters may be in the process of being printed, already printed or may be still 3 to be printed. This special character in the form of the continuous pattern is the validating character.

In the preferred embodiment an error checking circuit 25, which may be a parity checking circuit for example, detects whether or not there is an error in the line of characters being printed, already printed, or to be printed in the character line currently under the hammers 13. Error detecting circuits are well known; for example, see Patent Nos. 2,951,229; 2,954,433; and 3,142,839. Upon detecting an error, the circuit 25 applies an enabling signal to a hammer firing circuit 27, which in response to this enabling signal, energizes the solenoid of the hammer 23 to thus fire the hammer 23. Thus, an invalidating character in the form of a herringbone pattern will be printed opposite the character line currently under the hammers 23 to indicate that there is an error in the characters printed in this line.

Because the pattern 21 on the drum 11 is continuous, the firing of the hammer 23 does not have to be synchronized with the rotation of the drum. As a result, the error signal from the error checking circuit 25 can be applied to the hammer firing circuit 27 at almost any time. The hammer 23 can strike the pattern 21 to print the invalidating character even when the paper is moving to advance the next character line under the hammers 13. Because of this feature, the error checking circuit 25 has more time to detect whether or not the information being printed contains an error, thus making the error indicating function of the invalidating character more reliable.

In stead of firing the hammer 23 in response to an error signal, the hammer 23 could be fired in response to the absence of an error signal, in which case a validating character would indicate that there is no error in the line of characters opposite which it is printed. Also the hammer 23 could be controlled in response to more than one error checking circuit, if desired.

These and other modifications may be made to the above-described specific embodiment of the invention without departing from the spirit and scope of the invention, which is defined in the appended claims.

What is claimed is:

1. A high speed printer comprising:

a type carrier for moving a plurality of information characters to be printed past a printing line, said type carrier also supporting a validating character,

means to continuously move said type carrier past said printing line,

a plurality of hammers positioned along said print line,

means for producing an output signal determinative of the position of said information characters relative to said plurality of print hammers,

first means responsive to said output signal and to encoded information signals to operate said hammers to print,

means operable to detect errors in the information and to produce a signal indicating whether an error is detected,

a validating hammer, and

second means independent of said first means for opcrating said validating hammer to print said validating character in response to an output from said error detecting means.

2. A high speed printer as in claim 1 wherein said validating hammer is disposed at one end of said plurality of hammers.

3. A high speed printer as in claim 2 wherein said type carrier is a drum and said validating character is a continuous band around said drum.

4. A high speed printer comprising:

a drum defining a plurality of different characters to be printed, said drum also defining a continuous pattern extending around said drum,

printing means to select characters defined on said drum and to print the selected characters to thus print information,

means operable to detect errors in the information printed by said printing means and to produce a signal indicating whether an error is detected, and

means responsive to the signal produced by said error detecting means to print from said continuous pattern a character in the form of said continuous pattern.

5. A high speed printer comprising;

a drum defining a plurality of different characters raised in relief, said drum also defining a pattern raised in relief extending around said drum,

means to continuously rotate said drum,

a plurality of hammers positioned opposite said drum,

control means selectively operable to strike said hammers against said drum to print selected characters on said drum to thus print information,

an additional hammer positioned opposite s-aid continuous pattern,

an error detecting means operable to detect errors and to produce a signal indicating Whether an error is detected, and I means responsive to the signal produced by said error detecting means to strike said additional hammer against said pattern to print a character in the form of said continuous pattern.

References Cited UNITED STATES PATENTS WILLIAM B. PENN, Primary Examiner. 

1. A HIGH SPEED PRINTER COMPRISING: A TYPE CARRIER FOR MOVING A PLURALITY OF INFORMATION CHARACTERS TO BE PRINTED PAST A PRINTING LINE, SAID TYPE CARRIER ALSO SUPPORTING A VALIDATING CHARACTER, MEANS TO CONTINUOUSLY MOVE SAID TYPE CARRIER PAST SAID PRINTING LINE, A PLURALITY OF HAMMERS POSITIONED ALONG SAID PRINT LINE, MEANS FOR PRODUCING AN OUTPUT SIGNAL DETERMINATIVE OF THE POSITION OF SAID INFORMATION CHARACTERS RELATIVE TO SAID PLURALITY OF PRINT HAMMERS, FIRST MEANS RESPONSIVE TO SAID OUTPUT SIGNAL AND TO ENCODED INFORMATION SIGNALS TO OPERATE SAID HAMMERS TO PRINT, 